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1.
The climatic features of the formation of precipitation and their correlation with the baric situation in the Atlantic-European
sector are studied on the basis of the data of the Sevastopol and Feodosiya coastal hydrometeorological stations. As the source
data, we use the data arrays of daily precipitation at these stations in 1900–2005 and the data of reanalysis of the fields
of atmospheric pressure in the Atlantic-European sector. The comparative statistical analysis of daily precipitation for the
wet and dry summer and winter seasons and the estimates of extremely high levels of precipitation for the specified periods
of repeatability are presented. The existence of the dependence of occurrence of wet and dry winter seasons in Sevastopol
and Feodosiya on the large-scale baric fields in the Atlantic-European sector is confirmed.
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 43–51, July–August, 2008. 相似文献
2.
江南雨季地理区域及起止时间的客观确定 总被引:3,自引:0,他引:3
本文基于国家气象信息中心整编的全国1 675个台站观测资料以及NCEP/NCAR的再分析资料,定义了候降水指数,利用旋转正交经验函数分解(REOF)法对全国候降水的季节进程进行了诊断分析,得到了表征气候态降水逐候进程的南、北方模态及各自的时间系数,发现REOF第二模态对应降水季节进程中的江南雨季。综合考虑我国南方(31°N以南、110°E以东区域)气候态降水的候进程、降水季节进程(4-6月降水指数减去6-8月降水指数)年际变率以及雨季(4-6月降水指数)降水年际变率的一致性,客观定义了江南雨季的地理范围。利用客观划定区域内的降水指数、925hPa经向风以及西北太平洋副热带高压500hPa脊线位置3个指标,制定了判定江南雨季起止时间的方法,进而对1961-2012年江南雨季起止时间进行了客观确定,给出了江南雨季起止时间序列。本文旨在为规范江南雨季的监测提供参考和借鉴,并为其预测提供科学基础。 相似文献
3.
By using the NCEP reanalysis data for 1952–2000, we estimate the parameters of cyclones and anticyclones in the Black-Sea region and evaluate
the statistical characteristics of their variability for each season. It is shown that the frequency of cyclones decreases
in all seasons (except summer) as a result of the intensification of the North Atlantic Oscillation in the 1960–90s and the
displacement of the predominant paths of synoptic disturbances to the north. For anticyclones, we reveal the opposite trend.
The parameters of cyclones and anticyclones are characterized by quasiperiodic variations on the subdecadal scale also induced
by the North Atlantic Oscillation.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 47–58, November–December, 2007. 相似文献
4.
We consider an algorithm of prediction of nonstationary time series based on the method of analogs. Since the exhaustion of
a great number of versions is required for the adjustment of the parameters of the optimal prognostic model, we describe a
genetic algorithm used in this case. We consider several procedures of construction of prognostic models. The numerical results
are used to choose the procedure guaranteeing the minimum mean square error. The parameters of the model affecting the quality
of predictions are determined. The proposed method is tested by using the reanalysis data (NCEP/NCAR project) on the anomalies of the monthly average surface air temperature for 58 yr. The results of predictions are compared
with the estimates obtained by the linear regression method. It is shown that the method of analogs gives satisfactory results
even in the cases where the regression methods lead to errors equal to the variance of predicted series.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 70–80, July–August, 2007. 相似文献
5.
V. G. Bondur 《Izvestiya Atmospheric and Oceanic Physics》2011,47(9):1039-1048
We describe the specific features of the summer 2010 emergency conditions in the European part of the Russian Federation,
when an anomalous heat wave (the monthly mean temperatures in the summer months were 5–9°C higher than those for 2002–2009)
and prolonged blocking anticyclones led to large wildfires. We analyze their causes and consequences. The features of the
satellite system for operational fire monitoring (constructed at the Aerospace Scientific Center) and examples of its application
in summer 2010 are presented. On the basis of the results of processing of satellite images of low (250–1000 m), medium (∼30–50
m), and high (∼6 m) resolutions, we found that the total area covered by fire from March to November of 2010 amounted to approximately
10.9 million hectares for the entire territory of the country and and 2.2 million hectares for its European part. Daily histograms
of areas covered by fire in the summer months of 2010 were constructed. On the basis of these data and empirical models, we
estimate the daily emissions of carbon monoxide (CO) from wildfires in the summer months of 2010 for the European part of
Russia and Moscow oblast. On some days in August 2010, these emissions reached 15000–27000 t for the European part of Russia
and 3000–7500 t for Moscow oblast. On the basis of analysis of data from the AIRS spectrometer (Aqua satellite), we derived
the spatial distribution of CO concentrations at heights of 2 to 10 km above the territory of the Eastern and Central Europe.
Moscow was shown to have been most severely affected by smoke from wildfires occurring on August 6–9, 2010, when the concentrations
of harmful gases (CO2, CO, CH4, and O3) and aerosols in the air significantly exceeded both the daily and the one-hour maximum allowable concentrations. 相似文献
6.
S. F. Dotsenko 《Physical Oceanography》2005,15(3):133-141
Within the framework of a nonlinear model of long waves, we present the estimates of the parameters of tsunami waves along
the south coast of the Crimean Peninsula (from Cape Khersones to Cape Meganom) with a space resolution of 2.5 km. The numerical
analysis is carried out for four typical positions of the elliptic zones of generation and the range of magnitudes 6.5–7.5.
We study the space structure of waves and determine the amplitudes and periods of oscillations of the level at 11 points of
the analyzed part of the coastline of the Black Sea.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 3 – 10, May–June, 2005. 相似文献
7.
8.
A simple, yet efficient and fairly accurate algorithm is presented to estimate photosynthetically available radiation (PAR)
at the ocean surface from Global Imager (GLI) data. The algorithm utilizes plane-parallel radiation-transfer theory and separates
the effects of the clear atmosphere and clouds, i.e., the planetary atmosphere is modeled as a clear atmosphere positioned
above a cloud layer. PAR is computed as the difference between the incident 400–700 nm solar flux at the top of the atmosphere
(known) and the solar flux reflected back to space by the atmosphere and surface (derived from GLI radiance), taking atmospheric
absorption into account. Knowledge of pixel composition is not required, eliminating the need for cloud screening and arbitrary
assumptions about sub-pixel cloudiness. For each GLI pixel, clear or cloudy, a daily PAR estimate is obtained. Diurnal changes
in cloudiness are taken into account statistically, using a regional diurnal albedo climatology based on 5 years of Earth
Radiation Budget Satellite (ERBS) data. The algorithm results are verified against other satellite estimates of PAR, the National
Centers for Environmental Prediction (NCEP) reanalysis product, and in-situ measurements from fixed buoys. Agreement is generally
good between GLI and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) estimates, with root-mean-squared (rms) differences of
7.9 (22%), 4.6 (13%), and 2.7 (8%) Einstein/m2/day on daily, weekly, and monthly time scales, and a bias of only 0.8–0.9 (about 2%) Einstein/m2/day. The rms differences between GLI and Visible and Infrared Spin Scan Radiometer (VISSR) estimates and between GLI and
NCEP estimates are smaller and larger, respectively, on monthly time scales, i.e., 3.0 (7%) and 5.0 (14%) Einstein/m2/day, and biases are 1.1 (2%) and −0.2 (−1%) Einstein/m2/day. The comparison with buoy data also shows good agreement, with rms inaccuracies of 10.2 (23%), 6.3 (14%), and 4.5 (10%)
Einstein/m2/day on daily, weekly, and monthly time scales, and slightly higher GLI values by about 1.0 (2%) Einstein/m2/day. The good statistical performance makes the algorithm suitable for large-scale studies of aquatic photosynthesis. 相似文献
9.
By using the NCEP/NCAR reanalysis data sets for 1951–2001, we study the characteristics of Pacific cyclones. It is shown that the northeast-southwest
direction is predominant in the displacements of cyclones in the North Pacific. We study the variability of the field of surface
atmospheric pressure in different phases of the Pacific decadal oscillation characterizing the temperature anomalies on the
surface of the ocean in the region bounded by 20 and 60°N. It is shown that the decadal variations of the North Atlantic Oscillation
supported by the large-scale anomalies of the Pacific decadal oscillation is the most important cause of natural decadal oscillations
in the European region. We study and evaluate the regional response to the Pacific decadal oscillation by using, as an example,
the analysis of variations of the discharge of European rivers.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 13–23, July–August, 2007. 相似文献
10.
Three methods for identification cyclones in extratropical latitudes of the Northern Hemisphere (NH) (20°–80° L) are compared
based on reanalysis data (1948–2007) for the fields of the sea level pressure (SLP). Different characteristics of extratropical
cyclones, namely, their number, intensity, size, and lifetime, are analyzed. The effect of orographic effects for the identification
of cyclones and their trajectories is evaluated. The characteristics of extratropical cyclones are compared based on different
reanalysis data (National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR), ERA-40,
and ERA-INTERIM) with different spatial resolutions. 相似文献
11.
Within the framework of the linear theory of long waves, we study forced oscillation of liquid in a ring basin of variable
depth by using numerical methods. As a generator of waves, we use periodic (in time) variations of atmospheric pressure. The
action of the Coriolis force is taken into account. The liquid is regarded as homogeneous and inviscid. We analyze the dependences
of the structure of the free wave surface (the number and location of nodal lines) on the period and space distribution of
disturbing pressures.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 11–23, March–April, 2005. 相似文献
12.
Global surface layer salinity change detected by Argo and its implication for hydrological cycle intensification 总被引:1,自引:0,他引:1
Shigeki Hosoda Toshio Suga Nobuyuki Shikama Keisuke Mizuno 《Journal of Oceanography》2009,65(4):579-586
We investigated changes in the global distribution of surface-layer salinity by comparing 2003–2007 Argo-float data with annual
mean climatological surface-layer salinity data for 1960–1989 from the World Ocean Database 2005. The two datasets showed
similar patterns, with low values in subpolar and tropical regions and higher values in the subtropics. The recent Argo data
indicate that the contrast between low and high salinity has intensified in all areas except the subpolar North Atlantic.
The intensified contrast of the surface layer salinity was maintaining for 2003–2007. Using a simple method, we attempted
to estimate evaporation and precipitation changes on the basis of surface-layer salinity changes. The results show a high
probability that the global hydrological cycle has increased in the past 30 years. 相似文献
13.
T. Ya. Shul’ga 《Physical Oceanography》2006,16(6):313-321
By using the method of mathematical simulation, we study surge oscillations caused by the action of tangential wind stresses
in a bounded basin whose geometric parameters correspond to Lake Donuzlav. The dependences of the amplitudes of surges on
the magnitude and direction of the wind velocity are analyzed at several points of the coast.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 3–12, November–December, 2006. 相似文献
14.
Vadlamudi Brahmananda Rao Emanuel Giarolla Clóvis Monteiro do Espírito Santo Sergio Henrique Franchito 《Journal of Oceanography》2008,64(4):551-560
A comparison of monthly wind stress derived from winds of NCEP/NCAR (National Centers for Environmental Prediction/National
Center for Atmospheric Research) reanalysis and UWM/COADS (The University of Wisconsin-Milwaukee/Comprehensive Ocean-Atmosphere
Data Set) dataset (1950–1993), and of NCEP/NCAR reanalysis and satellite-based QuikSCAT dataset (2000–2006), is made over
the South Atlantic (10°N–40°S). On a mean seasonal scale, the comparison shows that these three wind stress datasets have
qualitatively similar patterns. Quantitatively, in general, from about the equator to 20°S in the mid-Atlantic the wind stress
values are stronger in NCEP/NCAR data than those in UWM/COADS data. On the other hand, in the Intertropical Convergence Zone
(ITCZ) area the wind stress values in NCEP/NCAR data are slightly weaker than those in UWM/COADS data. In the South Atlantic,
between 20° S–40°S, the QuikSCAT dataset presents complex circulation structures which are not present in NCEP/NCAR and UWM/COADS
data. The wind stress is used in a numerical ocean model to simulate ocean currents, which are compared to a drifting-buoy
observed climatology. The modeled South Equatorial Current agrees better with observations between March–May and June–August.
Between December–February, the South Equatorial Current from UWM/COADS and QuikSCAT experiments is stronger and more developed
than that from NCEP/NCAR experiment. The Brazil Current, in turn, is better represented in the QuikSCAT experiment. Comparison
of the annual migration of ITCZ at 20° and 30°W in UWM/COADS and NCEP/NCAR data sources show that the southernmost position
of ITCZ at 30°W in February, March and April coincides with the rainy season in NE Brazil, while the northernmost position
of ITCZ at 20°W in August coincides with the maximum rainfall of Northwest Africa. 相似文献
15.
Impact of the winter cooling on the variability of the thermohaline characteristics of the active layer in the Black Sea 总被引:1,自引:0,他引:1
The influence of the winter atmospheric forcing on the interannual variability of the Black Sea’s active layer’s thermohaline
structure during 1982–2008 is investigated. The results are based on the combined analysis of the hydrological measurements
from a ship, satellite measurements of the sea’s surface temperature (SST), and the NCEP/NCAR reanalysis data for the surface
air temperature (SAT). A high correlation between the variability of the winter mean SST/SAT and the thermohaline characteristics
of the active layer during the following warm season was found. It is shown that the winter atmospheric forcing significantly
affects the variability of the temperature, salinity, and density down to the 150–200 m depth, and this has to be considered
in the analysis of the interannual and long-term variability of the Black Sea’s active layer. 相似文献
16.
Operational Data Assimilation System for the Kuroshio South of Japan: Reanalysis and Validation 总被引:3,自引:5,他引:3
Masafumi Kamachi Tsurane Kuragano Hiroshi Ichikawa Hirohiko Nakamura Ayako Nishina Atsuhiko Isobe Daisuke Ambe Masazumi Arai Noriaki Gohda Satoshi Sugimoto Kumi Yoshita Toshiyuki Sakurai Francesco Uboldi 《Journal of Oceanography》2004,60(2):303-312
We describe an operational ocean data assimilation system for the Kuroshio and its validation using a nine-year reanalysis
(historical run from 1993 to 2001) dataset of upper-ocean state estimation in the North Pacific. The horizontal structure
of volume transport of the Ryukyu Current System (RCS) is shown from the reanalysis: The RCS is connected to the flow of the
subtropical gyre, and its volume transport gradually increases from south-east of Okinawa (5–10 Sv) to the east of Amami-Ohshima
Island (20 Sv). Comparing the reanalysis with independent observations on the southeast slope of the Amami-Ohshima Island
indicates that the root mean square differences (RMSDs) are 0.076 (0.037) m/s in the period of December 1998 to November 1999
(November 1999 to November 2000) respectively. The reanalysis field has a bias (3.1 Sv) of the volume transport of the RCS
and the RMSD (3.5 Sv) which is larger than the observed variability (2.81 Sv). Surface velocity and the Kuroshio axis south
of Japan are also examined. Comparison of the reanalysis and ADCP data gave maximum RMSD of 0.749 (0.271) m/s in the strong
(weak) current regions, respectively. The annual mean value of the axis error is 19 km in 1998. The RMSD of the error is at
most 50 km, in 294 cases in the observation period, which is smaller than the observed root mean square variability of the
axis (64 km).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
Shin-Ichi Ito Kazuyuki Uehara Takashi Miyao Hideo Miyake Ichiro Yasuda Tomowo Watanabe Yugo Shimizu 《Journal of Oceanography》2004,60(2):425-437
An observation line along the TOPEX/POSEIDON (T/P) ground track 060 was set to estimate the Oyashio transport. We call this
line the OICE (Oyashio Intensive observation line off-Cape Erimo) along which we have been conducting repeated hydrographic
observations and maintaining mooring systems. T/P derived sea surface height anomaly (SSHA) was compared with velocity and
transport on OICE. Although the decorrelation scale of SSHA was estimated at about 80–110 km in the Oyashio region, the SSHA
also contains horizontal, small-scale noise, which was eliminated using a Gaussian filter. In the comparison between the SSHA
difference across two selected points and the subsurface velocity measured by a moored Acoustic Doppler Current Profiler (ADCP),
the highest correlation (0.92) appeared when the smoothing scale was set at 30 km with the two points as near as possible.
For the transport in the Oyashio region, the geostrophic transport between 39°30′ N and 42°N was compared with the SSHA difference
across the same two points. In this case the highest correlations (0.79, 0.88 and 0.93) occurred when the smoothing scale
was set at 38, 6 and 9 km for reference levels of 1000, 2000 and 3000 db, respectively. The annual mean transport was estimated
as 9.46 Sv in the 3000 db reference case. The Oyashio transport time series was derived from the T/P SSHA data, and the transports
are smaller than that estimated from the Sverdrup balance in 1994–1996 and larger than that in 1997–2000. This difference
is consistent with baroclinic response to wind stress field.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
We perform the analysis of the time spectra of four tsunamis generated in the Black Sea by the earthquakes of 26.07.1927,
11.09.1927, 26.12.1939, and 12.07.1966. For the analysis of the spectra, we used digitized marigrams obtained for 12 points
of the Black-Sea coast. The obtained spectra are, as a rule, multimode and have 1–4 spectral maxima. One maximum corresponds
to the periods typical of tsunami waves and the other maxima correspond to the oscillations of the sea level with lower frequencies.
It seems likely that the events of tsunami are accompanied by low-frequency oscillations of the level caused by the atmospheric
forcing, seiches, or other factors. In numerous cases, the oscillations from the predominant energy range lie outside the
characteristic range of periods of the tsunami waves.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 5, pp. 21–30, September–October, 2007. 相似文献
19.
Hideo Kawai 《Journal of Oceanography》2003,59(2):163-172
Using natural coordinates, we have derived a criterion for the inertial instability of arbitrarily meandering currents. Such
currents, governed by the eccentrically cyclogeostrophic equation, are adopted as the basic current field for the parcel method.
We assume that any virtual displacement which is given to a water parcel moving in the basic field has no influence on this
field. From the conservation of mechanical energy for a virtual displacement we derive an inertial instability frequency ω
m
= [(f + 2u/r)Z]0.5 for the eccentrically cyclogeostrophic current, where f is the Coriolis parameter, u the velocity (always positive), r the radius of curvature of a streamline (negative for an anticyclonic meander), and Z the vertical component of absolute vorticity. If ω
m
2 is negative, the eccentrically cyclogeostrophic current becomes unstable. Although the conventional, centrifugal instability
criterion, derived from the conservation of angular momentum in a circularly symmetric current field, has a certain meaning
for a monopolar vortex, it contains a radial shear vorticity that is difficult to use in arbitrarily meandering currents.
The new criterion ω
m
2 contains a lateral shear vorticity that is applicable to arbitrarily meandering currents. Examining instabilities of concentric
rings with radii of 50–100 km, we consider reasons why the anticyclonic supersolid rotation has been very much less frequently
observed than the cyclonic supersolid rotation, despite a prediction of some common stability and a rapid change in radial
velocity gradient for the former. Classifying eccentric streamlines into the large and small curvature-gradient types, we
point out that the large-gradient curvature in anticyclonic rings is apt to be unstable.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
Masahisa Kubota Naoto Iwasaka Shoichi Kizu Masanori Konda Kunio Kutsuwada 《Journal of Oceanography》2002,58(1):213-225
We have constructed ocean surface data sets using mainly satellite data and called them Japanese Ocean Flux data sets with
Use of Remote sensing Observations (J-OFURO). The data sets include shortwave radiation, longwave radiation, latent heat flux,
sensible heat flux, and momentum flux etc. This article introduces J-OFURO and compares it with other global flux data sets
such as European Centre for Medium Range Weather Forecasting (ECMWF) and National Center for Environmental Prediction (NCEP)
reanalysis data and da Silva et al. (1994). The usual ECMWF data are used for comparison of zonal wind. The comparison is carried out for a meridional profile
along the dateline for January and July 1993. Although the overall spatial variation is common for all the products, there
is a large difference between them in places. J-OFURO shortwave radiation in July shows larger meridional contrast than other
data sets. On the other hand, J-OFURO underestimates longwave radiation flux at low- and mid-latitudes in the Southern Hemisphere.
J-OFURO latent heat flux in January overestimates at 10°N–20°N and underestimates at 25°N–40°N. Finally, J-OFURO shows a larger
oceanic net heat loss at 10°N–20°N and a smaller loss north of 20°N in January. The data of da Silva et al. in July show small net heat loss around 20°S and large gain around 20°N, while the NCEP reanalysis (NRA) data show the opposite.
The da Silva et al. zonal wind speed overestimates at low-latitudes in January, while ECMWF wind data seem to underestimate the easterlies.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献